Method and means for securing treads to steel subtreads



June 30, 1931. L. DEL TURCO 1,812,504

METHOD AND-MEANS FOR SECURING TREADS To STEEL SUBTREADS Filed Jan. 24, 1930 2 Sheets-Sheet l vmmmboz v LOU/5 13:54 rmco is chrome/ s L. DEL TURCO June 30, 1931.

METHOD AND MEANS FOR SECURING TREADS T0 STEEL SUBTREADS 2 Sheets-Sheet 2 I III! II I III.) lllllll I'll lllll llllllllll Illllllll lllllllllll llllllll II H q LOU/5 05L Tmco Filed Jan. 24. 1930 mu Q wan Patented June 30, 1931 PATENT OFFICE LOUIS DEL TURGO, F NEWARK, NEW JERSEY IEETHOD AND MEANS FOR SECURING TREADS TO STEEL SUBTREADS Application filed January 24, 1930. Serial No. 423,052.

This invention r'elates'to a novel method and means for securing treads such as those made of terrazzo, stone, slate, marble and the like, to the pressed steel sub-treads of a constructed stairway.

One of the objects of this invention is to provision of a method and means for securing to a preconstructed pressed steel stairway a plurality of such treads.

Another object of this invention is the provision of a method and means for rigidly securing, against warping, a plurality of treads to the metal framework of a precon structe'd stairway.

Various other objects and advantages of the invention than those hereinabove mentioned will appear more fully hereinafter. It is to be understood that the specific forms shown are merely illustrative and hence the detailed description thereof is not to be taken as limiting the invention itself.

In the art of creating marbledike stairways formed of a plurality of treads, or, as is known in the trade, non-slip alundum aggregate treads, difficulty has been encountered in the provision of a method and means for securing such aggregate treads to a metal framework stairway when in the condition left by the ironworkers. This difiiculty not only has been encountered with respect to the aggregate treads mentioned, but has been found to prevail when treads of stone, slate, marble and the like have been used. I, therefore, propose to delineate a method whereby any type of tread may be secured to a sub tread, and I do not intend to limit myself to the provision of a methodand means for the securing of merely aggregate treads to subtreads. The treads as usually made and brought on to the job are completed articles, having been manufactured in the shop, and when deliveredto a particular building for use therein are in properly seasoned condition and polished. The difficulty encounr tered usually arises when attempt is made to secure such finished treads in a neat nonwarpable and inconspicuous fashion. It is possible to drill holes through the ends of such treads and through the steel subtreads, pass screws therethrough and secure such treads to the subtreads by bolting. Such method, however, although it would prevent the undesirable warping of the ends of the tread away from the sub-tread would have a very inartistic effect. To eliminate such undesirable effect constitutes one of the purposes of this invention which is to provide a cheap, rugged method and means of securing treads to a metal stairway in a manner whereby the securing means do not impair the artistic effect.

Referring now to the drawings, it will be seen that in:

Figure l is a perspective view of a stairway showing my novel structure;

Fig. 2 is a front elevational View of the stairway shown in Figure 1,;

Fig. 3 is a bottom view of a metal step partially broken away;

Fig. 4 is a sectional view taken along the line 44= in Figure 1;

Fig. 5 is an enlarged partially broken sectional view of one end of the tread shown in Fig. 4;

Fig. 6 is a sectional view taken along the line- 66 of Fig. 5;

Fig. 7 is a broken perspective view of my dovetail unit;

F 8 is a broken perspective view of my adjustable securing hanging;

Fig. 9 is a variant embodiment of the construction shown in Fig. 5;

Fig. 10 is a second variant embodiment of the construction shown in Fig. 5.

Similar reference characters refer to similar parts throughout 'thevarious views.

Referring now to the figures, it will be seen that at 1, I show the under face of a pressed steel subtread of a metal preconstructed stairway having at 2 a riser running upward to the next higher metal sub-tread, and at 3 a riser dropping downward to the next lower sub-tread. This meta-l sub-tread is drilled at four points, two holes at either end thereof to receive therethrough machine screws or toggle headed screws 4, L, 4, 4. Vhen the underside of the stairway is accessible and headed screws can he slipped into the drill holes from under the stairway ordinary machine screws may be used. However, when the union ' While still in a plastic state have mounted therein at either end thereof metal dovetails derside of the stairway is inaccessible, after the holes are drilled, collapsible toggle laeaded bolts are inserted from the upper face of said sub-tread throughthe bolt holes. 'VVhen the heads of such toggle bolts expand beneath the stairway they accomplish the same function as the ordinary machine screw head.

A p the metal sub-tread there is placed a securing flanging 5, such as is shown in Fig. 8, having slots 6, 6 therein. The shape of such flanging may be, asisshown in Fig. 8, of a generally L-shape with the elongated side of the L laid against the flat surface of the upper side of the sub-tread. The slots 6, 6 render the flanging 5 adjustable sidewise on the screws or bolts 4, 4. When the proper adjustment of such-securing fianging is attained nuts '7, 7 are tightened down on eachof said screws orbolts 4 and thus the securing flanging is secured to the upper face of the metal sub-tread with the shorter leg of the L-shaped fiang'ing rising up, as is shown in Fig. 5 at 8. When each pressed steel metal sub-tread l'has'mounted thereon two of these securing fiangings 5 the metal sub-tread is then-in a condition to have mounted thereon a properly manufactured aggregate tread, 11. These aggregate treads, designed for such mounting are actually re-enforced with a plurality of re-enforcing bars 9, 9, 9 and 10, such as are shown in Fig. 7. The object of such metal-dovetails is to form the cementitious block on its underside and at either end thereof before hardening into a dovetail shape. The metal form which is pressed into the cementitious material might be removed therefrom after the material has taken its form, but it has been found more expedient from the viewpoint of commercial success and cost to leave such metal dovetails which are of cheap metal, positioned in place after hardening. The metal dovetail may extend from the rear face of the tread almost to the front nosing of the treads beneath the re-enfo-rc'ing bars and be made inconspicuous at the front'nosing of the tread by filling in all exposed portions thereof after the tread is mountedas a unit upon the sub-tread. If, instead of using a tread originally composed of plastic material which, when hardening, will set and contain therein the metal dovetail forms, the tread that is used be of stone, slateor marble, I accomplish the provision of dovetail indentations in such stone, slate or marble tread by cutting out, by hand or machine, the material to give such indentations rather than by forcing the metal dovetail form into the plastic material, as 'I have heretofore recited. Since it is, of course, immaterial how the tread obtain the two dovetail indentations requisite to this invention, I deem that this cutting out of the dovetailindentationis the equivalent of the forming of such indentation in the tread material of an originally plastic tread. The completed tread of terrazzo material, or the like, having at either end thereof one of the formed dovetail indentations is, after being polished and seasoned, ready for mounting upon the metal sub-tread which has secured thereto the L- shaped metal securing flanging. All that is then necessary to effect such securing of the tread .to the fianging is to spread upon the upper face of the metal sub-tread with a trowel a layer of cementitious mixture, 12, which fills the loop of the L, the dovetail indentations on the under face of the sub-tread and provides the body thickness 12 of cementitious material between the under face of the tread generally and the upper face of the sub-tread. When such filling material is inserted within the dovetail shaped indentations and within the preshaped metal securing fianging the effect will be that'upon the hardening of such securing cementitious material a cement dovetail will be formed which is secured to the upper face of the subtread by the L-shaped metal securing flanging and to the tread at the dovetail joint.

It is, of course, apparent that the securing flanging need not be of the single L type shown in Fig. 5, but maybe o-fatype wherein the L joint is duplicated as shown in Fig. 9. Such mounting would necessitate, of course, the provision of eight .bolt holes and eight screws and nuts on each sub-tread. The

securing effect would be increased by the duplicating of such securing fianging, andon jobs where the time spent in securing the fianging such as 5a5a would not be prohibitive it is possible that this variant embodiment may be beneficially used. A further embodiment of securing flanging which would necessitate a still greater degree of adjustment before being ultimately secured to the upper face of the metal subtread is that shown in Fig. 10 of the U-type 55. .For this variant type of flanging but the usual tWo-bolt'holes at either end of the metal sub-treads would be needed, and the holding efiect would beduplicated and be substantially the equivalent of that shown in Fig. 9. It is apparent, however, that such type of securing flanging would necessitate the expenditure of-more time inthe mounting thereof and constitutea more expensive type of unit. It is believed to be apparent in all of the above types of securing :fianging embodiments that it becomes necessary that the securing end ofsuch'flanging be allocated in every instance within the dovetail shaped indentation of the undersideof'thetread. It is, of course, therefore preferable that the dovetail shaped indentation be large enough so that when the tread is seated over the securing fianging but little adjustment thereof will act to allocate the securing end of such flangings within such indentations.

As I have already described, the structure recited need not be limited in its application merely to terrazzo aggre ate treads, but may be adapted to use with treads made of any commercial material used for such purpose, such as stone, slate, marble, and the like, in which case, of course, the necessity of a dove tail metal form is no longer present and such form can be dispensed with.

Further tl an this it is of course apparent that the dovetail shaped indentations and se' curing flangings need not be allocated so that they run transversely of the treads but may be disposed in any direction across the surface of the treads and sub-treads which will either meet the mechanical needs of a given installation or secure a firmer holding effect. W hen the size of a given installation requires that the treads be made in sections adapted to be joined together this possible variant disposition of the securing means in any prechosen direction is, of course, particularly advantageous in the securing of such sectional treads together by a common securing of each of the sectional treads to the subtreads.

From the foregoing, it will be apparentthat I have provided a relatively simple structure for carrying out the objects set forth above. I am aware that numerous changes in the details of construction and relative arrangement of parts will occur to those skilled in this art, and I do not, therefore, desire to be limited to the exact structure disclosed and illustrated by me, but rather to the scope of the invention as set forth in the appended claims.

What I desire to secure by United States Letters Patent is:

1. The method of securing a tread to a subtread which consists in forming a dovetail shaped indentation on the under surface of such tread, mounting a securing means on the upper face of the sub-tread and filling around said securing means and into said dovetail shaped indentation a cementitious material.

2. The method of securing a tread to a subtread which consists in mounting upon the sub-tread a securing fianging, forming an indentation in the tread, mounting said tread so that said indentation thereon registers with the securing flanging, mounting said tread on said sub-tread and filling said indentation with a cementitious material which surrounds said securing flanging.

3. The method of securing a terrazzo tread to a metal sub-tread which consists in forming a plurality of indentations on the under surface of said tread, mounting a plurality of securing fiangings on the upper surface of said sub-tread and interposing between said securing flangings and said indentations a cementitious material.

4. In a structure substantially of the type described, a tread having allocated on the bottom thereof two dovetail shaped indentations, a sub-tread having therethrough a plurality of bolt holes, a securing fianging secured to the upper surface of said sub-tread by a plurality of bolt-s and nuts, said flanging being so allocated that the securing portion thereof falls within the confines of said indentation and a cementitious material surrounding said flanging and filling said in dentation.

5. In a structure substantially of the type described, a tread having grooves therein, a sub-tread, means mounted on said sub-tread and seating in the grooves in said tread'for permanently and rigidly securing said tread to said sub-tread.

. 6. In a structure substantially of the type described, a metal sub-tread, securing means mounted thereon, a tread having grooved indentations on the under surface thereof, and a binding material securing said tread to said sub-tread at said indentations.

7. In a structure substantially of the type described, a tread having a plurality of dovetailed indentations running transversely thereof, a sub-tread having mounted thereon a plurality of L-shaped securing flangings and a cementitious material securing said flangings to said tread at said dovetail indentations.

8. In a structure substantially of the type described, a tread having a plurality of dovetail shaped indentations running transversely thereof, a sub-tread having secured thereto on the upper surface thereof a plurality of U-shaped securing flangings adapted to register with said indentations, and a cementitious filling body adapted to secure said tread to said securing flangings at said indentations.

. 9. In a structure substantially of the type described, a sub-tread, a securing flanging adapted to be secured thereto, means securing said flanging to said sub-tread, and means including a preformed metal member mounted on said tread for securing said tread to said fianging.

10. The method of securing a tread .to a subtread which consists in mounting upon the sub-tread a securing flanging, cutting an indentation in the tread, mounting said tread so that said indentation thereon registers with the securing flanging, mounting said tread on said sub-tread and filling said indentation with a cementitious material which surrounds said securing fianging.

11. In a structure substantially of the type described, a tread having a plurality of dovetailed indentations cuttherein and running transversely thereof, a sub-tread having mounted thereon a plurality of securing a tread.

flanging-s; and alcementitious material securing said flanging to said tread at said dovetail identations.

"12. Ina-structure substantially of the type described, a tread having transverse grooves therein, asub-tread, means mounted on said sub-tread and seating 111 the transverse grooves in'said treadfor permanently and rigidly securing said tread to said sub-tread. -13. astruoture substantially of the type described, a tread, bars disposed in said tread to reinforce-the same, a sub-tread, a securing flanging mounted on said sub-tread, means for securing said flanging tosaid tread, and means comprising collapsible head toggle bolts for securing said flanging to the subtread.

14. In a structure substantially of the type described, a tread, a sub-tread, an L-shaped flanging mounted on said sub-tread, and

means 'for securing said flanging to said tread. I Y 15. In-astructuresubstantially of the type described, a-tread having a dovetail indentation therein, a sub-tread, two opposed L- shaped securing flangings mounted on said sub-tread-and disposed Within the dovetail indentation,- and means for securing said flangings to said tread.

16. In a structure substantially of the type described, atread, a sub-tread, a securing flanging mounted on said sub-tread, said flanging being slotted for adj ustability upon the means for securing it to the sub-tread, and lneans for securing said flanging to said 1'7. In a structure substantially of the type described,'a formed cementitious tread having a dovetail indentation therein, a rigid dovetail element disposed in said indentation, a sub-tread, a securing flanging mounted on said sub-tread, and means for securing said flanging to said tread. v

18. In a structure substantially of the type described, a sub-tread, a tread extending beyond said sub-tread and "having a dovetail shaped indentation therein,the exposed por 1 tion of which is filled in to present asmooth under side for said tread, a securing flanging on saidsub-tread, and'means for securing said flanging to said tread. v

19. In a structure substantially of the type described, a sub-tread, a tread of greater Width than the Width of said sub-tread seated on saidsub-tread and extending therefrom and having a nosing portion thereon WhlCh maybe of various pleasing contours,

andimeans for rigidly securing said tread to said-sub-tread.

In testimony whereof I have hereunto set my'hand on this 21st day of January A. 'D.,

. LOUIS DELTUROO, 

